# Schema evolution — ETL / ELT Pipelines

Source: https://www.geekswithgeeks.com/en/etl-elt/etl-elt-07

> Apply Schema evolution with clear evidence.

## Understand Schema evolution

For **Schema evolution**, begin with the problem it solves. Identify the inputs, constraints, and observable outcome before choosing an implementation.

## Practise deliberately

Create one small example for **Schema evolution** and verify its result before expanding it.

## A useful comparison

**Schema evolution** is like a route plan: it keeps each step connected to a destination.

Check your reasoning.

**Quiz:** What is the best first step for Schema evolution?

- [x] Define the goal and constraints.
- [ ] Copy an unverified example.
- [ ] Skip measurement.

*Answer:* Define the goal and constraints.. A clear goal and constraints make decisions reviewable.